Many types of textile processing equipment, such as carding machines and airlay web formers, are designed to receive textile fiber from a bale in the form of a batt wherein the batt is formed of a collection of tufts of fiber. In the operation of such textile equipment, the tufts are conventionally pulled or taken whole into the textile equipment. Exceptionally large tufts may overload the textile equipment by providing too much fiber at once. Thus, it is preferred that the batts are formed with smaller tufts therein and the feed rates are set to accommodate the largest remaining tufts. In addition, bale opening equipment and perhaps other equipment is used to open the bales of fiber and break the tufts into smaller clumps of fiber to facilitate less overloading of equipment and higher feed rates.
To fully understand the problem and solution proposed by the present invention, a common understanding or definition of the word "tuft" may be necessary. In this specification, "tuft" has a somewhat different meaning from that which is commonly used to describe the fiber in a tufted carpet. The word "tuft" is used herein to describe clumps of fiber or a bunch of individual fibers attached together wherein the individual fibers in the tuft are cohesively connected and have not been opened up, separated or combed by carding equipment, airlay equipment or the like. It should be noted that tufts are often clumped together especially when pressed into a batt, but the tufts tend to maintain individual identity by their stronger cohesive attachments. In general, fiber is in the form of tufts when it is raw fiber haven been taken directly from a bale. Tufts are often formed in man-made fiber at the time the tow is chopped or crimped. Many natural fibers, such as cotton, form into tufts because they grow around seeds to provide a sort of "parachute" to carry and disperse seeds by wind from the plant. Such tufts may be separated into smaller tufts by cleaning and picking equipment used to process the cotton into usable fiber. The individual fibers are typically not truly entangled with one another, although it may sometimes appear to the untrained observer that they are. Rather, the fibers are attached or connected together by cohesive forces, although such cohesive forces are not so strong that the tufts cannot be easily pulled apart by hand.
Tufts are light and lofty with fibers radiating out therefrom thus being generally reactive to any flow of air, such as the natural fiber is for dispersing the seeds away from the plant. Each tuft generally comprises a substantial number of individual fibers which are quite randomly oriented therein. To convey a visual sense of what a tuft looks like, the fibers which are used by DuPont in the making of its Sontara.RTM. spunlaced fabrics are typically between 3/4" to about 1 1/2" in length and are relatively straight or have a small amount of crimp therein. The tufts formed by such fibers are randomly sized puff balls of irregular shape and density from 1/2" to 3 1/2" in diameter. Fibers having longer lengths or more crimp will typically make for tufts having a different range of sizes probably including larger tufts. The tufts do not have the uniform density or regular shape of a cotton ball one normally has in their medicine cabinet, but there is some analogy to the size and loftiness of a cotton ball. It should be noted that the fibers in a cotton ball have been combed or carded to separate the individual fibers and the fibers have been arranged to provide the rounded shape, so the comparison is for illustration purposes only. In any event, one should understand that the tufts are rather light, soft and readily deformable. The tufts also tend to move with and be very reactive to any flow of air in their vicinity.
As noted above, the feedrates of carding equipment and airlay web formers are limited by the size of the largest tufts in the batt. The batts are typically formed by chute feeders which are designed to form a batt of preferably uniform thickness and density. Such chute feeders simply stack the tufts of fiber in a channel having a width approximately that of the carding machine and a thickness of approximately the thickness of the batt. For examples of conventional chute feeder design, there are a number of issued U.S. patents illustrating chute feeders, such as U.S. Pat. No. 3,738,476; U.S. Pat. No. 4,154,485; U.S. Pat. No. 4,449,272; U.S. Pat. No. 4,930,190; and U.S. Pat. No. 5,157,809.
By the present invention, a batt may be created by an improved chute feeder wherein the batt is formed of essentially the same fiber tufts as conventional batts, but the feed rate of the new style batt into textile equipment may be increased without regard to the size of the largest tuft. The new styled batt is believed to provide improvement for most textile machinery arranged to be fed such batts made of tufts, but the performance is particularly unexpected and dramatic when considered for carding machines. The functional difference between the conventional batt and the new batt is that the new batt is designed or arranged to provide a natural resistance to an entire tuft being pulled whole into the feed mechanism of the textile machine. With the new style batt, the tufts are either drafted out (elongated) between the feed rolls and the lickerin roll or the tuft is simply disassembled by the lickerin at the feed rolls. In comparison, a conventional batt from an above described conventional chute feeder readily provides whole tufts to the lickerin roll. As such, the tuft must be drafted and/or disassembled on the carding roll. As described before, whole tufts tend to fill the capacity of the card and extra large tufts may overload the capacity. Thus, feed rates for cards have historically been set to accommodate the largest tufts to avoid overloading the carding roll.
By observing that the pick up mechanisms for most types of textile processing machinery often pick up such clumps or tufts in their entirety, it was speculated that if a batt could be formed which did not allow whole tufts to be fed into the carding machine, that the feed rate could be increased. In tests, the new type of batt provides a considerable improvement in throughput for a carding machine. At the present time, the improvement is approximately three times current throughput, but it is believed that production rates approaching six times current throughput, and maybe higher, are attainable. This is astounding under any circumstances, but it is particularly amazing in light of the fact that most conventional carding technology has been around for many decades.
The basic underlying structural difference between the conventional batt and the new batt relates to the orientation of the tuft in the batt. In the conventional batt, the tufts end up stacked in the chutes and are compressed down by the weight of the tufts on top thereof. As such, the tufts tend to become flattened out horizontally like pancakes in an orientation which is essentially perpendicular to the batt. When such batts are delivered to the feed mechanism, typically turned 90.degree. to be in a horizontal orientation, the tufts or layers are upright and vertical so that they may be easily peeled from the batt and pulled whole onto the lickerin roll. In the new type of batt, the tufts are also flattened, but they are flattened so that they lie essentially flat within the batt or close to parallel with the plane of the batt.
In the operation of the new chute feeder for making the new style batt, the tufts tend to form layers or "shingles" which are highly overlapped in a generally linear imbricated pattern. Thus, the shingles are arranged such that when the batt is compressed between two rolls or two conveyor belts or the like, each shingle is pressed between layers of shingles from both above and below for a substantial part of its length (in the machine direction). Thus, the new batt is arranged to retain the majority of each shingle, and therefore the majority of each tuft, pinched between the feed rolls as the leading edge thereof is pulled onto the lickerin roll. As the batt is continuously fed to the lickerin, the shingles and tufts are "nibbled" or pulled apart across the layers of the batt rather than the lickerin pulling a single layer or tuft whole. Thus, the "new" batt enables fiber to be fed to textile equipment at a more constant rate.
Accordingly it is an object of the present invention to provide a process and equipment for creating a batt suitable for being fed to textile equipment that overcomes the deficiencies and drawbacks of the conventional arrangements as described above.
It is more particularly an object of the present invention to provide a process and apparatus for creating a batt suitable for being fed to textile equipment wherein the tufts of fiber comprising the batt are controlled so as not to be delivered intact to the textile equipment.
The above and other objects of the invention are accomplished by the provision of a process for assembling a batt comprising providing loose, highly lofted tufts. In the process, the loose, highly lofted tufts are provided into the top portion of a generally vertically oriented chute to pass with a flow of air down therein to a foraminous conveyor belt generally at the bottom portion thereof. The foraminous conveyor belt moves along a machine direction under the chute to carry the batt being formed thereon out of the bottom of the chute and to a carding machine or the like where the tufts are collected on the foraminous conveyor belt to form overlapping shingles by drawing air down through the belt from the upper surface thereof such that the air transmission rate through the belt is substantially uniform along the machine direction taking into account that the fiber batt is substantially thicker at one end of the hopper as compared to the other.